Systems and methods for unmanned aerial painting applications

ABSTRACT

Various embodiments of the present disclosure are directed to an Unmanned Aerial System (UAS) for applying a liquid to a surface. According to various embodiments, the UAS includes an Unmanned Aerial Vehicle (UAV) including flight control mechanisms. The UAV is configured to receive first control signals and to adjust an operational configuration of the flight control mechanisms in response to the first control signals. The UAS further includes a delivery assembly coupled to the UAV, where the delivery assembly is configured to receive second control signals and to apply the liquid to the surface located proximately to the UAV in response to the second control signals. The UAS further includes a control unit coupled to the UAV and the delivery assembly, the control unit configured to transmit the first and second control signals to the UAV and the delivery assembly, respectively.

BACKGROUND

Unmanned aerial vehicles (UAVs), or simply drones, have been designed,built, and flown for decades. No longer strictly limited to recreationalusers, such as radio-controlled model airplane enthusiasts who sendminiscule replicas of World War II fighter aircraft airborne, nor toreconnaissance experts working for clandestine arms of the governmentwho construct and build flying platforms that are packed with sensorsand electronics and capable of being remotely piloted from a controlstation a hemisphere away, the use of UAVs is expanding rapidly intocommercial applications as well.

Relatively recently, a prominent American businessman envisioned a worldwhere UAVs can deliver consumer items to a customer's doorstep withinthirty minutes of being ordered online. While this vision may yet besome years from being realized, UAVs have already been used inapplications related to wildfire mapping, disaster management, thermalinfrared power line surveys, telecommunications, weather monitoring,aerial imaging/mapping, television news coverage, sporting events,moviemaking, environmental monitoring, and oil and gas exploration. Itis safe to say that the growth of Unmanned Aircraft Systems (UAS) thatutilize UAVs is expected to grow exponentially. Indeed, global annualspending on research, development, testing, and evaluation of UAS wasabout 6.6 billion U.S. dollars in 2013 and is expected to grow to 11.4billion by 2022.

While the growing proliferation of UAS has the potential to transformhuman life and bring us one step closer to a society straight from ascience fiction novel, there are a host of unresolved issues lurkingbehind this growth, perhaps the biggest one being public safety. Forexample, since existing UAS are managed remotely and rely upon wirelesssignals to receive operational commands, a UAS can be hacked and itsmission bent to destructive purposes. In 2012, a University of Texasprofessor and a group of students demonstrated this weakness byintercepting a Global Positioning System (GPS) guided UAS, using a OPSdevice that they created.

Integrating UAS safely into national airspace also represents anightmare for the entities responsible for control and safety of theNational Aerospace System (NAS). In March of 2014, a NationalTransportation Safety Board (NTSB) administrative law judge overturnedthe Federal Aviation Administration's (FAA) first-ever fine against adrone operator, ruling that when the operator flew an unmanned droneover the University of Virginia in 2011, “there was no enforceable FAArule or FAR (Federal Aviation Regulation) applicable to model aircraftor for classifying model aircraft as an UAS.”

The U.S. Congress has asked the FAA to formulate a plan for safeintegration of UAS into commerce by the fall of 2015. Meanwhile, the FAAhas officially stated on their website that anyone who wants to fly anaircraft—manned or unmanned—in U.S. airspace needs some level of FAAapproval. In the regulatory vacuum that currently exists, there is aneed for UAS and methods of operating UAS that are both safe to thepublic and stand a good chance of avoiding the strict regulatoryoversight that appears likely to be introduced by the FAA in the nearfuture.

SUMMARY

In accordance with some embodiments of the present disclosure, apainting system is configured to be coupled to a UAV, where the UAVincludes flight control mechanisms and is configured to receive firstcontrol signals and to adjust an operational configuration of the flightcontrol mechanisms in response to the first control signals. Thepainting system includes a delivery assembly coupled to the UAV, and isconfigured to receive second control signals and to apply a liquid to asurface located proximately to the UAV in response to the second controlsignals. The painting system further includes a control unitcommunicatively coupled to the UAV and the delivery assembly, where thecontrol unit configured to transmit the first and second control signalsto the UAV and the delivery assembly, respectively.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective-view diagram illustrating an example UAVsuitable for use with embodiments of the present disclosure.

FIG. 2 is a plan-view diagram illustrating a UAV component of a UAS forpainting applications in accordance with some embodiments of the presentdisclosure, where the UAV component includes an attached paint deliverysubsystem.

FIG. 3 is a profile-view diagram further illustrating the UAV of FIG. 2.

FIG. 4 is a simplified schematic diagram illustrating some components ofa remote control station of a UAS in accordance with embodiments of thepresent disclosure.

FIG. 5 is a simplified schematic diagram illustrating a UAS for paintingapplications in a typical idealized operating environment, namely,proximate to a wall that may form part of a house or much largerstructure such as an office building or skyscraper.

FIG. 6 is a plan-view diagram illustrating a UAV component of a UAS forpainting applications in accordance with other embodiments of thepresent disclosure, where the UAV component includes an attached paintdelivery subsystem.

FIG. 7 is a profile-view diagram further illustrating the UAV of FIG. 6.

FIG. 8 is a simplified schematic diagram illustrating a UAS for paintingapplications in another typical idealized operating environment, namely,proximate to a bridge.

FIG. 9 is a diagram illustrating aspects of a simplified User Interface(UI) for UAS painting applications in accordance with exampleembodiments.

FIG. 10 is a diagram further illustrating aspects of a simplified UI forUAS painting applications in accordance with example embodiments.

FIG. 11 is a diagram further illustrating aspects of a simplified UI forUAS painting applications in accordance with example embodiments.

FIG. 12 is diagram further illustrating aspects of a simplified UI forUAS painting applications in accordance with example embodiments.

FIG. 13 is a diagram further illustrating aspects of a simplified UI forUAS painting application in accordance with example embodiments.

FIG. 14 is a flow-chart illustrating a method of painting a structurewith a UAS for painting applications in accordance with some embodimentsof the present disclosure.

DETAILED DESCRIPTION

In view of the concerns identified above, it is desirable to develop UASand methods for performing mundane yet dangerous tasks using UAS thatreduce or eliminate dangers to human beings who traditionally performthe same tasks, as well as to bystanders who may be in proximity to theoperational UAS. It is also desirable to develop UAS and methods forperforming tasks using UAS that are considered safe to the generalpublic by aviation regulatory authorities, and therefore, easilyapproved. The inventors have recognized that painting applications,especially painting that is performed for the routine maintenance oflarge structures such as buildings and bridges, is one such area whereUAS have not yet been fully exploited, and where UAS can achieve greatcost savings while simultaneously reducing or eliminating the dangerassociated with these tasks.

In the following detailed description, several example embodiments ofUAS for painting applications will be described in detail. Those skilledin the art will recognize that the inventive aspects or teachingsdescribed in conjunction with this limited selection of embodiments maybe combined in a variety of different ways to arrive at embodiments thatare not specifically described herein, yet nonetheless exhibit theinventive aspects as taught by this disclosure. As such, the variousexample embodiments described herein should be considered illustrativeonly and not limiting in any way, as the specific claims accompanyingthis disclosure will delineate and define the breadth and scope of theinvention.

Furthermore, out of necessity, the following detailed description doesnot provide an exhaustive description of every detail necessary to builda UAS for painting applications in accordance with embodiments of thepresent disclosure. Rather, areas where those skilled in the art wouldbe expected to possess a certain threshold level of knowledge areomitted so that the inventive aspects of the example embodiments may befocused upon. It is expected that the knowledge possessed by those ofordinary skill in the art at the time of filing this application,coupled with the inventive teachings found herein, will be sufficient toprovide those of ordinary skill the ability to manufacture, program, anduse UAS for painting applications as conceived and envisioned by theinventors.

A note on terminology is appropriate at this point. In the followingdetailed description, the words “including” or “includes” are used inthe non-exclusive sense. That is, if a system, component, assembly,etc., is described as including an element A, an element B, and anelement C, there may be one or more other, undescribed, elements aswell. Similarly, the words “comprising” or “comprises” are also used inthis non-exclusive sense.

Throughout the specification, if the inventors wish to impart anyparticular or specialized meaning to any word or term, this will beclearly signaled in the text by phrases such as “the term _(——————)refers to . . . ,” “the word _(——————) is defined as . . . ,” or other,similar language. In the absence of such an explicit definition, it isexpected that the meaning of a word will be apparent based upon itsordinary and customary meaning coupled with whatever context in which itis used. For example, in the following detailed description, when afirst element is described as being “coupled” to a second element, thisshall indicate that the first element is attached directly to the secondelement, perhaps with a coupling such as a screw, bracket, rivet,adhesive, etc., without any intervening elements. On the other hand,when a first element is described as being “connected” to a secondelement, this shall mean that there may be any number of interveningelements attached between the first and second elements.

Next, inventive aspects that are characteristic of embodiments of thepresent disclosure will be described below with reference to the Figuresthat were identified above. In general, the first number of a referencenumber is indicative of the Figure in which the element is firstdescribed, i.e., the number “210” begins with the numeral “2,”indicating that the element first appeared in FIG. 2 and was firstdescribed with reference to FIG. 2. Throughout the following detaileddescription, like numbers refer to like elements. Finally, the reader isreminded that the Figures accompanying this detailed description arerendered for ease in conveying inventive aspects, and are notnecessarily drawn to scale.

System Overview

Some embodiments of the present disclosure provide a UAS that includes aUAV and a paint delivery subsystem connected to the UAV. In theseembodiments, an operator of a UAV can remotely direct or pilot a UAV tohover in close proximity to a structure, and control the connected paintdelivery subsystem in order to apply paint to the structure in a desiredmanner. In these embodiments, the skill of the operator controlling theUAV is of importance because the UAV should be maintained at an optimumdistance from the structure so that paint may be applied evenly and withminimal dispersion while simultaneously avoiding objects that should notbe painted such as windows and doors.

In other embodiments of the present disclosure, a UAS that includes aUAV and a paint delivery subsystem is capable of being automaticallycontrolled by a programmable computer through a software application. Inthese embodiments, a UAS may include sensors that are capable ofdetermining a precise location of a UAV relative to a structure. Aprogrammable computer may operate a UAV to fly along a predeterminedflight path while maintaining a precise position of the UAV relative tothe structure by automatically adjusting flight control elements of theUAV in response to changing wind conditions. In these embodiments, aprogrammable computer, based upon the location information, may alsocontrol the paint delivery system attached to the UAV to precisely applypaint to the structure in a desired manner.

In still other embodiments of the present disclosure, a UAS includes aUAV and a paint supply reservoir that is connected to the UAV andconfigured to remain on the ground while the UAV is in flight. In theseembodiments, one or more pumps may be used to deliver paint that is heldin the paint supply reservoir to a nozzle that is attached to the UAV.There may be larger, heavier, ground-based pumps that are connected tothe paint supply reservoir that perform the task of lifting the paint tothe airborne UAV, and a smaller, lighter pump that is carried aloft bythe UAV itself and that provides the optimum pressure for delivery ofpaint from the nozzle. In these embodiments, paint is delivered to thenozzle via an umbilical that may include one or more flexible tubes. Insome embodiments, each of the flexible tubes may supply a differentcolor of paint to the nozzle of the UAV. In other embodiments, anumbilical may optionally include a lightweight power cable to supplyelectrical power to the UAV and/or the attached paint deliverysubsystem, although in most cases the power necessary to operate the UAVand/or the paint delivery subsystem can be provided by a battery that iscarried aboard the UAV.

In some embodiments of the present disclosure, a UAS for paintingapplications includes a UAV and a paint bladder that is carried by theUAV while the UAV is in flight. In these embodiments, the UAS includes asmaller, lighter pump carried by the UAV itself that provides theoptimum pressure for delivery of paint from the nozzle of the paintdelivery subsystem. In these embodiments, a paint bladder may bedetachable from the UAV so that empty bladders may be swapped out forfull bladders relatively easily. Because the paint bladder and theamount of paint it can store in these embodiments is necessarily limiteddue to the lifting capacity of the UAV, these embodiments would be idealfor smaller touch-up painting applications where the number of requiredrefills is limited, as the replacement of a paint bladder wouldtypically be performed by a human operator of the UAS. In theseembodiments, the tubing that delivers the paint from the paint bladderto the nozzle of the paint delivery subsystem is also preferablydetachable from the UAV so that different colored paint may be usedwithout contamination of paint of one color with paint of a differentcolor.

In some embodiments of the present disclosure, a UAS for paintingapplications includes a control unit that is operable to provide a userinterface to an operator of a UAV, and is operable to transmit controlsignals to the UAV. For example, control signals may include flightcontrol signals for controlling the flight of a UAV, and/or paintingcontrol signals for controlling the application of paint via the nozzleof a paint delivery subsystem attached to a UAV.

UAV

FIG. 11 is a perspective-view diagram illustrating a UAV 100 suitablefor use in example embodiments of the present disclosure. As envisionedby the inventors, UAS for painting applications utilize UAVs, such asUAV 100, that are capable of hovering and maintaining a fixed positionabove the ground and in close proximity to buildings and otherstructures for extended periods of time. As such, UAV 100 isrepresentative of a wide variety of existing UAVs that may beincorporated into UAS for painting applications in accordance withexample embodiments.

Referring to FIG. 1, UAV 100 includes a circular body 140, four arms 120disposed at substantially 90 degree intervals around the circumferenceof body 140 and extending radially outward from body 140, and fourflight control mechanisms or rotors 110. Each rotor 110 is disposed at adistal end of a corresponding arm 120. UAV 100 further includes acontroller 130 disposed in a central location on body 140, and fourlanding struts 150, which are coupled to arms 120 and extend downwardlyat an angle from arms 120. Rotors 110 provide lift and steering for UAV100, giving it the ability to hover in place and maintain a fixedposition relative to another object, such as a wall or bridge. Anoperational configuration of rotors 110 is changed in response to thereceived flight control signals, and as a result a flight speed, flightdirection, and position of UAV 100 may be controlled to a high degree ofaccuracy. Controller 130 includes a battery (not shown) to provide powerto UAV 100 and a wireless receiver (not shown) for receiving wirelessflight control signals from a ground-based control station, which willbe described in further detail below.

Because UAV 100 has four rotors 110, it is of a type generally known asa “quad-copter” design. Other UAVs suitable for use with otherembodiments may have a different number of rotors, such as six rotors(“hexa-copter”) or even eight rotors (“octo-copter”). Generallyspeaking, if the size of the rotors is equal, a UAV with more rotors iscapable of producing more lift, but it also requires more energy topower the rotors as well. In the example embodiments of UAS for paintingapplications that are described herein, a UAV should generate enoughlift to enable both itself and whatever payload it may be carrying tobecome airborne. Weight and lift considerations such as these are normalflight engineering problems that are well-known to those of ordinaryskill, and will not be explained in further detail herein.

UAS with Ground-Based Paint Supply

Collectively, FIGS. 2, 3, 4, and 5 illustrate some important componentsof a UAS 500 having a ground-based paint supply in accordance withexample embodiments, such as UAV 200 (FIGS. 2 and 3), ground station 400(FIG. 4), and paint supply reservoir 530 (FIG. 5). In particular, FIGS.2 and 3 are plan-view and profile-view diagrams, respectively, whichillustrate a UAV 200 component of UAS 500, where UAV 200 includes anattached paint-delivery subsystem. FIG. 4 is a simplified schematicdiagram illustrating a ground control station 400 component of UAS 500.FIG. 5 is a simplified schematic diagram further illustrating UAS 500,as well as showing UAS 500 in a typical idealized operating environment,namely, proximate to a wall 520 that may form part of a house, a shed,or a much larger structure such as an office building or skyscraper.

Referring first to FIGS. 2 and 3, UAV 200 is a “quad-copter” designsimilar to UAV 100 (FIG. 1), but additionally includes a paint deliverysubsystem, which comprises a paint supply line 205, a boom 210, a bumper220, a pump 225, and a nozzle 230. Additionally, UAV 200 includes aLIght Detection And Ranging (LIDAR) unit 240 disposed above bumper 220and slightly behind it. Boom 210 extends radially outward from body 140of UAV 200, preferably at a location that is midway between two of thearms 120. Boom 210 is also preferably longer than a combined radiallength of an arm 120 and a rotor 110. Bumper 220 is disposed at a distalend of boom 210, and preferably has a curved shape as shown in the planview of FIG. 2. Also as shown in FIG. 2, bumper 220 is preferablydisposed such that it extends radially outward beyond nozzle 230 andLIDAR unit 240.

Using LIDAR technology, astronomers have been able to measure a distancefrom the earth to the moon to the nearest millimeter. LIDAR technologyis mature and well-known, and further details regarding LIDAR technologywill not be reproduced here. Suffice to say, there are numerous designsfor LIDAR unit 240 that are suitable for use in UAS 500.

Advantageously, LIDAR unit 240 provides the capability of easilymeasuring a distance between a surface to be painted and LIDAR unit 240to a high degree of precision, typically to the nearest centimeter,which is sufficient for most painting applications. Because LIDAR unit240 will typically be operating no more than 20 or 30 centimeters awayfrom a surface to be painted (contrast this with an earth to moonranging application of thousands of miles), the power, size, and weightrequirements for LIDAR unit 240 are correspondingly low. Thus, UAS 200is capable of lifting and powering LIDAR unit 240 relatively easily.

In some embodiments, in addition to accurately measuring a distancebetween LIDAR unit 240 and a surface to be painted, LIDAR unit 240 iscapable of distinguishing a nature of the surface itself. For example,based on the reflected returns, LIDAR unit 240 may determine whether asurface is covered with a coating of paint or a coating of rust. Areaswhere rust is found may be recorded as areas of future concern and/oradditional steps may be taken to address the rust problem, such asapplication of a rust inhibitor, followed by a subsequent application ofpaint. Alternatively or additionally, LIDAR unit 240 may determine if asurface is bare metal, bare stone, bare wood, etc. This capability isparticularly helpful in routine painting applications such as bridgemaintenance where periodic spot maintenance may be more cost-effectivethan completely repainting an entirety of a bridge structure everyseveral years.

In preferred embodiments, and in particular for painting applicationswhere a human operator is flying UAS 200, LIDAR unit 240 and nozzle 230are disposed relative to each other such that a distance between LIDARunit 240 and a surface to be painted is the same as the distance betweennozzle 230 and the surface to be painted. However, any known offsetbetween a location of LIDAR unit 240 and nozzle 230 may easily beaccounted for using software.

In a typical painting scenario, UAV 200 is flown such that nozzle 230 isdisposed in close proximity to and aimed towards a surface that is to bepainted. That is, UAV 200 is typically flown such that boom 210substantially forms a right angle between itself and a surface to bepainted. In usual situations, a surface to be painted is the closestsurface to the UAV 200 and therefore poses the greatest threat to thesafe flight envelope of UAV 200. Together, boom 210 and bumper 220advantageously prevent rotors 110 of UAV 200 from approaching tooclosely to a surface to be painted. Because bumper 220 extends radiallyoutward past nozzle 230 and LIDAR unit 240, bumper 220 alsoadvantageously prevents nozzle 230 and LIDAR unit 240 from being damagedif bumper 220 contacts the surface to be painted during flight.

Paint supply line 205 is connected to an underside of body 140 and boom210, and extends radially outward to where it terminates at nozzle 230.Pump 225 is disposed on an underside of boom 210, in line with paintsupply line 205, and operates to provide a pre-determined optimum amountof pressure to the paint (or alternatively, any other liquid) that isdelivered to nozzle 230. Together, pump 225 and nozzle 230 arecontrolled by controller 130 to selectively spray the paint carried inthe paint supply line 205 onto a surface proximate to nozzle 230. Aswill be described below with reference to FIG. 5, a supply end of paintsupply line 205 may be disposed to draw paint from a ground-based paintsupply reservoir 530.

In alternative embodiments, UAV 200 may include more than one boom210/bumper 220 combination extending radially outward from body 140.While such embodiments with extra booms/bumpers would typically not havean associated paint supply line 205, they would still be beneficial froma safety standpoint, especially in situations where UAV 200 may beexpected to be flown proximate to surfaces that are roughly concave innature, such as an “inner” corner where two walls intersect at a ninetydegree angle.

FIG. 4 is a simplified schematic diagram illustrating some components ofa remote control station 400 of UAS 500 in accordance with embodimentsof the present disclosure. As illustrated, remote control station 400includes a manual control unit 410 and a laptop computer 420 that isoperable to display data 430 to an operator of UAS 500.

Manual control unit 410 is capable of sending signals to UAV 200 orreceiving signals from UAV 200 via wireless communication link 440.Laptop computer 420 is capable of sending signals to UAV 200 orreceiving signals from UAV 200 via wireless communication link 450.Additionally, manual control unit 410 and laptop computer 420 arecapable of exchanging signals via wireless communication link 460. Inalternative embodiments, wireless communication link 460 may be replacedwith a wired communication link, such as a USB connection, an Ethernetconnection, or the like, because manual control unit 410 and laptopcomputer 420 will typically be positioned in close proximity to theother during operation of UAS 500. In still other example embodiments,functions of manual control unit 410 and laptop computer 420 could becombined into a single, specialized ground control unit.

According to example embodiments, an operator of UAS 500 can use manualcontrol unit 410 to remotely pilot UAV 200 and operate the attachedpaint delivery subsystem. Alternatively, using laptop computer 420, anoperator of UAS 500 can pre-program a flight path and/or a paintapplication profile using laptop computer 420 and specialized softwarethat includes a user interface, and then simply monitor the progress ofUAV 200 as it navigates the flight path and applies the paint to astructure that is to be painted.

Generally speaking, data 430 that is displayed on laptop computer 420may include any type of information that may be relevant to an operatorof UAS 500. For example, data 430 could include location data that isassociated with the location of UAV 200, flight data that is associatedwith the flight profile of UAV 200, environmental data that isassociated with the environmental conditions in the immediate proximityof UAV 200 that are relevant to the application of the paint or to theflight conditions, or system status data that is associated with keyoperational indicators of UAS 500.

As illustrated in FIG. 4, an example of environmental data includes airtemperature, but environmental data may also include relative humidity,wind direction, and wind speed. As illustrated in FIG. 4, examples oflocation data include an altitude of UAV 200 and Universal TransverseMercator (UTM) coordinates for UAV 200, but location data may alsoinclude latitude, longitude, and a distance between bumper 220 and asurface that is to be painted, such as data derived from LIDAR unit 240.An example of flight data may include a visual representation (e.g. aschematic diagram or a map) of a structure (wall, bridge, building,etc.) that is being painted by UAS 500 and a relative position of UAV200 with respect to the structure. An example of system status data mayinclude an amount of battery life remaining in controller 130, and thusan estimate of how much more time UAV 200 may remain airborne. Otherexamples of system status data may include error messages, such aswhether components of the paint delivery subsystem, such as nozzle 230,are working properly.

Data 430 that is displayed on laptop computer 420 may be collected byappropriate onboard sensors that are included in UAV 200, such as LIDARunit 240 or other sensors within controller 130, or alternatively may begathered from other sensors or sources that are not onboard UAV 200. Forexample, as is well-known, latitude and longitude coordinates arereadily calculated based upon Global Positioning System (GPS) signalsthat are generated by OPS satellites. Instead of being disposed on UAV200, a GPS receiver may be included in ground control station 400 andstill provide roughly the same latitude and longitude informationwithout adding extra weight to UAV 200.

FIG. 5 is a simplified schematic diagram further illustrating UAS 500for painting applications in a typical idealized operating environment,namely, proximate to a wall 520 that may form part of a house or muchlarger structure such as an office building or skyscraper. Referring nowto FIG. 5, one important consideration associated with UAS for paintingapplications in accordance with embodiments of the disclosure, such asUAS 500, is the ability to determine an accurate location of UAV 200,and more particularly, nozzle 230, relative to wall 520. To address thisconcern UAS 500 includes two fixed radio emitters 510 that are disposedat a known height H and a known distance D relative to wall 520. Radioemitters 510 emit a radio signal that controller 130 is capable ofreceiving via wireless radio links 512 and 514. Using known signalstrength comparison techniques, height H, and distance D, controller 130is capable of determining a position of nozzle 230 relative to wall 520to the nearest centimeter, which is sufficient for most paintingapplications.

UAS 500 additionally includes a paint supply reservoir 530 and a pump535. Paint supply reservoir 530 is operable to hold a supply of paint ofa desired color and composition, while pump 535 is operable to force thepaint upwards through paint supply line 205, towards UAV 200. Pump 535provides the majority of the work required to deliver paint to anoperational height of UAV 200, while pump 225, which was describedabove, provides the optimal pressure for the paint that is delivered tonozzle 230.

During operation of UAS 500, UAV 200 operates to apply paint that isdelivered to it while in flight by pump 535. Obviously, a maximumoperational height of UAV 200 is limited by a length of paint supplyline 205. During operation of UAS 500, both paint supply reservoir 530and pump 535 remain on the ground. In some embodiments, paint supplyreservoir 530 may be a small 5 gallon bucket that is transported on achild's wagon. In other embodiments, paint supply reservoir 530 may bepart of a large mobile tanker trunk.

Optionally, according to alternative embodiments of the presentdisclosure, there may be a power supply line bundled or attached to thepaint supply line 205, whose function is to provide electrical power toUAV 200 from a ground-based power source. In such embodiments, UAV 200may have a much smaller on-board battery, or perhaps no battery at all,if power is supplied to it from the ground. In preferred embodiments,however, it would be desirable to have a small battery onboard that issufficient to return UAV 200 to the ground in a controlled manner if forsome reason the power supply line was disconnected or the ground-basedpower source failed.

It is contemplated that with the precise location-finding capabilitiesprovided by LIDAR unit 240 and radio emitters 510, UAV 200 is capable ofautonomously traversing a flight path that allows UAS 500 toconsistently apply a uniform coating of paint to selected areas of wall520. Using laptop 420, operators of UAS 500 may load pre-defined paintprofiles for any desired structure. For example, a typical paint profilemay include overall dimensions of the structure, and locations and sizesof areas that are not to be painted (windows, doors, vents, etc.) Withthe appropriate paint profile and precise location information providedby LIDAR unit 240 and radio emitters 510, UAS 500 is capable ofprecisely, efficiently, and safely applying paint to any and all desiredareas of wall 520.

According to some embodiments of the present disclosure, two or morepaint profiles can be merged to form a new paint profile. For example,suppose an artist is commissioned to design a mural that will be paintedon one side of a 30-story building. Further suppose that there isalready a first paint profile for the skyscraper that preciselyspecifies the surfaces of the skyscraper that can be painted. Using acanvas that has the same relative dimensions as the skyscraper, theartist could conveniently complete the mural on the canvas, take apicture of the canvas, and with the appropriate software package,translate the picture into a second paint profile for the skyscraper.The first and second paint profiles may be merged to form a third, newpaint profile that, in its simplest form, specifies where UAS 500 shouldapply paint, and what color of paint, to the side of the building inorder to render an accurate duplication of what the artist completed onthe canvas.

According to some example embodiments, laptop computer 430 translatesthe third paint profile into flight control signals and painting controlsignals that are transmitted to UAV 200 by ground control station 400.Ground control station 400 is operable to start UAV 200, maneuver UAV200 to a starting point for the third paint profile, command and controlUAV 200 to apply paint in accordance with the third paint profile, andreturn UAV 200 safely to the ground upon completion of the third paintprofile. In this fashion, UAS 500 is capable of saving hundreds of manhours and eliminating dangers associated with people working from greatheights.

Safety Advantages of UAS with Ground-Based Paint Supply

From a safety perspective, one particularly advantageous aspect of UAS500 that was described above, as well as other similar embodiments thatutilize a ground-based paint supply reservoir, is the presence of apaint supply line 205 connecting ground-based paint supply reservoir 530to UAV 200. According to example embodiments, paint supply line 205 notonly functions to supply paint to nozzle 230 of UAV 200, it also servesan additional purpose of tethering UAV 200 and limiting its operationalarea to the vicinity of a structure that is being painted. According toexample embodiments of the present disclosure, a paint supply line mayadditionally include strong and lightweight rope, cable, or similarmaterial that is capable of preventing UAV 200 from breaking free ofground-based paint supply reservoir 530. Thus, even in the event of amalfunction of the UAV or active control of the UAV being lost due tohackers, the operational area of the UAV is limited to a hemisphericalvolume defined by a length of a paint supply line 205 and the locationwhere paint supply line 205 is fixed in place, eliminating the threatthat a runaway or malfunctioning UAV might cause to other mannedaircraft in the area.

As was mentioned above, there are currently no FARs in place thatregulate the operation of UAS, and at the time of this writing one canonly guess as to what final form any of the FAA's future proposals willtake. Regardless, example embodiments according to the presentdisclosure that include a tether in the form of a paint supply line willlikely be considered safe by the FAA for several reasons, and thereforerequiring of less scrutiny and regulatory oversight.

For example, there is an existing FAR, 14 C.F.R. §101, which regulatesthe operation of moored balloons, kites, amateur rockets and unmannedfree balloons. Moored balloons are those that are attached to thesurface of the earth or an object thereon and that have a diameter ofmore than 6 feet or a gas capacity of more than 115 cubic feet. 14C.F.R. §101.1(a)(1). Kites are defined as weighing more than five poundsand intended to be flown at the end of a rope or cable. 14 C.F.R.§101.1(a)(2). Under 14 C.F.R. §101.1(b), a gyro-glider (a mannedaircraft with unpowered rotors that is designed to be towed by a boat oran automobile) is considered to be a kite.

UAVs attached to ground-based paint supplies by paint supply lines inaccordance with embodiments of the present disclosure may besubstantially smaller in size than the moored balloons defined by 14C.F.R. §101, and may be substantially smaller or comparable in weight tothe gyro-glider or kites defined by 14 C.F.R. §101. 14 C.F.R. §101.7(a)generally prohibits any person from operating a moored balloon or kitein a manner that creates a hazard to other persons or their property.Thus, because a tethered UAS for painting application in accordance withexample embodiments is both smaller in size than a moored balloon andlighter or roughly equal in weight to a kite under existing FARs, it ishighly likely that operations of such tethered UAS may be granted ablanket approval conditioned upon operation of the tethered UAV in anon-hazardous manner.

Furthermore, 14 C.F.R. §101.13(a) provides that no person may operate amoored balloon or kite less than 500 feet from the base of any cloud,more than 500 feet above the surface of the earth, from an area whereground visibility is less than three miles, or within five miles of theboundary of any airport. However, 14 C.F.R. §101.13(b) carves out anexception to these operational prohibitions and explicitly states thatthe rules of paragraph (a) do not apply to the operation of a mooredballoon or kite operating below the top of any structure and within 250feet of it, as long as such shielded operation does not obscure anylighting on the structure itself.

Thus, since tethered UAS for painting applications in accordance withembodiments of the present disclosure will practically always beoperated below the height of a structure to be painted and well within250 feet of a structure to be painted, it is likely that theseembodiments would not be considered overly dangerous by the FAA due tothe UAVs being shielded from other commercial aircraft by the proximityof the structure that they are painting. If these embodiments are not ofa great concern to the FAA because of their tethered operation, then theregulatory hurdles that must be followed for operational approval arelikely to be fewer in number, and also relatively easy to obtain. Thus,these safety advantages of the disclosed embodiments may potentiallyequate to a great convenience and savings in both cost and time tooperators of UAS for painting applications as well as other applicationswhere UAVs are operated close to structures that shield passengeraircraft and other manned aircraft from the UAVs.

UAS with Airborne Paint Supply

Collectively, FIGS. 4, 6, 7, and 8 illustrate some important componentsof a UAS 800 having an airborne paint supply in accordance with exampleembodiments, such as ground control station 400 (FIG. 4) and UAV 600(FIGS. 6 and 7). In particular, FIGS. 6 and 7 are plan-view andprofile-view diagrams, respectively, which illustrate a UAV 600component of UAS 800, where UAV 600 includes an attached paint-deliverysubsystem according to other embodiments of the present disclosure. FIG.8 is a simplified schematic diagram further illustrating UAS 800, aswell as showing UAS 800 in a typical idealized operating environment,namely, proximate to a bridge 810.

UAS 800 shares many of the same components as UAS 500 that was describedabove, such as ground control station 400. Accordingly, where commoncomponents have already been described with reference to UAS 500, aduplicative description will be avoided in favor of concentrating on theelements where UAS 800 differs from UAS 500.

Referring to FIGS. 6, 7, and 8, the most obvious difference between UAS500 and UAS 800 is that UAS 800 includes a paint supply canister 610that may be detachably affixed to body 140 of UAV 600. The holdingcapacity of paint supply canister 610 is much less than that of paintsupply reservoir 530, and embodiments such as UAS 800 would be moresuitable for applications where smaller structures are to be painted, orwhere basic touch-up painting is all that is required. It iscontemplated that in other example embodiments, paint supply canister610 may have substantially the same form, fit, and function as a typicalaerosol spray paint can. According to example embodiments, when paintsupply canister 610 is empty, an operator of UAS 800 may swap it with adifferent paint supply canister 610 relatively easily using aquick-disconnect (not shown) disposed between paint supply canister 610and paint supply line 205.

Another notable difference between UAS 800 and UAS 500 is that bumper620, which is disposed at a distal end of boom 210, is substantiallyflat. Additionally, rather than LIDAR unit 240, UAS 800 includes a CCDcamera array 630 that is mounted to a front surface of bumper 620. Insome embodiments, CCD camera array 630 may be inset relative to a frontsurface of bumper 620 so that bumper 620 provides protection to CCDcamera array 630. According to example embodiments, CCD camera array 630is operable to collect image data from immediately in front of bumper620. This image data is collected by controller 130 and transmitted toground station 400 via wireless link 450, where the image data may bedisplayed on laptop computer 430. In this manner, an operator of UAS800, who is manually flying UAV 600, may visually ascertain how closenozzle 230 is to bridge 810, as well as visually inspect surfaces ofbridge 810 for signs of rust or other damage.

Instead of using radio emitters 510 to determine accurate positioninformation, UAS 800 includes a number of reflectors 820 that areaffixed to different places on bridge 820 at known positions. Reflectors820 are preferably metallic, and are known as corner-cube reflectors,because the surfaces of reflectors 820 form 90 degree corners, whichhave the property of reflecting any incident energy away from thereflectors 820 at substantially the same angle. By periodicallytransmitting radio or optical energy using wireless links 812 and 814,and measuring the reflected returns, controller 130 may determine theprecise location of UAV 600 relative to bridge 810.

Unlike UAS 500, UAS 800 does not possess a paint supply line 205 and thecorresponding functionality and safety advantages associated with itthat were described above. However, according to alternative embodimentsof the present disclosure, a simple tether composed of lightweight cableor rope may be included in order to achieve the same safety advantagesas paint supply line 205 of UAS 500.

User Interface (UI) for Ground Control Station of UAS

As was illustrated in FIG. 4, a ground control station 400 suitable foruse with example embodiments may include a laptop computer 420. Laptopcomputer 420 is operable to accept inputs from a human operator of UAS500 or UAS 800, and translate those inputs into flight control signalsand/or painting control signals that are transmitted to UAV 200 or UAV600. A variety of different software programs may be stored in a memoryof laptop computer 420, that when executed by laptop computer 420,provide human operators of UAS 500 or UAS 800 with a User Interface (UI)through which flight path and paint control selections can beaccomplished. In general, inputs from human operators of UAS 500 or UAS800 can be accomplished using the keyboard and/or mouse hardwarefunctionality provided by laptop computer 420. Typically, a UI providesflight control options and paint control options by allowing a humanoperator to select from different items on a drop-down menu, specifyparticular numerical values using the keyboard, or the like.

Collectively, FIGS. 9 through 13 illustrate portions of a simplifiedexample UI 900 for painting applications suitable for use with UAS 500or UAS 800. In particular, FIGS. 9-13 illustrate a variety of exampledrop-down menus, each menu having a number of example menu items orselections that are intended to demonstrate the sheer variety of optionsthat are possible for painting applications and that are limited only byhuman creativity. For purposes of this disclosure, an example UI that isimplemented using a laptop computer and drop-down menus was selected forillustrative purposes only, other UIs suitable for use with exampleembodiments could be, for example, implemented with other mobile devicessuch as a tablet computer, a smart phone, Google Glass® or the like.

FIG. 9 is a diagram illustrating a simplified UI 900 for UAS paintingapplications in accordance with example embodiments. UI 900 includes anumber of dropdown menus, such as File menu 910, Draw menu 920, Uploadmenu 930, Calibrate menu 940, and Options menu 950. As illustrated inFIG. 9, when File menu 910 is selected, a drop-down box 960 appears.Drop-down box 960 includes a number of operator-selectable items such asOpen paint profile 970, Save paint profile 980, and Exit 990. The itemsfound in File menu 910 allow an operator of UAS 500 or UAS 800 to openor view an existing paint profile (Open paint profile 970), save changesthat are made to a paint profile (Save paint profile 980), or to exitthe UI 900 (Exit 990).

In accordance with example embodiments, paint profiles are data filesthat define the shape, size, and color(s) of a desired painting on anintended structure to be painted. For every desired painting on anintended structure, there are myriad possible flight paths that could betraversed by a UAV component of a UAS painting system relative to theintended structure in order to complete the paint profile. In accordancewith some embodiments, the particular flight path associated with aparticular paint profile is selected based upon which flight pathresults in the least power consumption by UAV component. In otherembodiments, the particular flight path associated with a particularpaint profile is selected based upon which flight path results in thefastest completion of the paint profile. Depending on the paint profile,the most efficient flight path doesn't necessarily result in the fastestcompletion of the paint profile. In the embodiment of UI 900, theability to select between these two alternatives is not illustrated butrather one or the other is automatically calculated for every paintprofile. Thus, UI 900 is particularly easy for human operators of UAS500 or UAS 800 to comprehend and utilize, as flight control signals forcontrolling UAV 200 or UAV 600 are calculated behind the scenes by aprocessor of laptop computer 420 under control of program software,based upon the desired paint profile, and transmitted to UAV 200 or UAV600 without active operator involvement.

FIG. 10 is a diagram further illustrating a simplified UI 900 for UASpainting applications in accordance with example embodiments. Inparticular, FIG. 10 illustrates in further detail Draw menu 920. WhenDraw menu 920 is selected, drop-down box 1010 appears. Drop-down box1010 includes a number of operator-selectable items such as Modifyexisting paint profile 1020 and Create new paint profile 1030. Byselecting the Modify existing paint profile 1020 option, a humanoperator can make changes to an existing paint profile, for example,change the paint color selection from Olive Drab green to BattleshipGrey.

By selecting the Create new paint profile 1030, a human operator maycreate a new paint profile completely by scratch, specifying colors,shapes, and sizes of a new painting. As was described above, a new paintprofile may be created by merging two or more existing paint profiles.According to some example embodiments, paint profiles may be createdusing a drawing application for a tablet computer, resulting in picturesthat are automatically scaled to the dimensions of the surface to bepainted. According to some example embodiments, paint profiles may becreated from existing photographs or drawings, such as data files in the.jpeg or .pdf format.

FIG. 11 is a diagram further illustrating a simplified UI 900 for UASpainting applications in accordance with example embodiments. Inparticular, FIG. 11 illustrates in further detail Upload menu 930. WhenUpload menu 930 is selected, drop-down box 1110 appears. Drop-down box1110 includes a number of operator-selectable items such as Upload jpeg1120 and Upload pdf 1130. As was indicated above in the discussion ofFIG. 10, UI 900 allows an operator to create new paint profiles usingdata files in .jpg or .pdf format. Thus, when Upload jpeg 1120 or Uploadpdf 1130 is selected, further selection mechanisms are offered to theoperator so that she may choose the desired file from which to createnew paint profiles.

FIG. 12 is a diagram further illustrating a simplified UI 900 for UASpainting applications in accordance with example embodiments. Inparticular, FIG. 12 illustrates in further detail Calibrate menu 940.When Calibrate menu 940 is selected, drop-down box 1210 appears.Drop-down box 1210 includes a number of operator-selectable items suchas Position 1220, Find reference 1230, and Scale 1240. When Position1220 is selected, UAS may use onboard sensors as was described above toorient itself at a pre-determined starting point relative to a buildingor other structure in preparation for completing a selected paintprofile. When Find reference 1230 is selected, a UAS may be commanded tomaneuver to a specified reference point on a building or structure andresume completing a selected paint profile from that specified referencepoint. When Scale 240 is selected, a UAS for painting applications mayuse onboard sensors of the type described above to use an existing paintprofile that is sized for a different building and scale itappropriately so that it may be used on a structure having differentdimensions.

FIG. 13 is a diagram further illustrating a simplified UI 900 for UASpainting applications in accordance with example embodiments. Inparticular, FIG. 13 illustrates in further detail Options menu 950. WhenOptions menu 950 is selected, drop-down box 1310 appears. Drop-down box1310 includes a number of operator-selectable items such as Colors 1320and Transparency 1330. By selecting Colors 1320, a further list of paintcolors is presented to the operator, which the operator may use tospecify or change particular paint colors in selected paint profiles. Byselecting Transparency 1330, one or more selected paint profiles may bedisplayed in overlay fashion on a display screen of laptop 420, givingthe operator an idea of what a conglomeration of several different paintprofiles will look like after being painted on a desired structure.

Methods of Operating UAS for Painting Applications

FIG. 14 is a flow-chart illustrating some processes in a method 1400 ofoperating a UAS for painting applications in accordance with someembodiments of the present disclosure. As was indicated above, in someembodiments laptop computer 420 is capable of calculating a flight pathfor a UAV component of a UAS based upon a desired paint profile. In someembodiments the associated flight path is determined based uponefficiency, i.e., the flight path that requires the UAV component toconsume the least amount of power. In other embodiments, the associatedflight path for a particular paint profile is determined based uponspeed, i.e., the flight path that completes the paint profile in theleast amount of time.

Speed and efficiency are not the only possible selection criteria for asuitable flight path, however. The inventors contemplate that there isalso a significant amount of entertainment that can be derived by themere act of watching a UAV begin to paint a picture on a surface of alarge structure and attempting to guess what the final picture will be.FIG. 14 illustrates a method 1400 that is aimed at doing just that, byrandomly selecting flight paths that UAV utilizes the paint the desiredpaint profile. Randomly selecting flight paths is neither a speedy orefficient way of completing a paint profile, but in some situations theentertainment value it provides could be a worthwhile goal. For example,community interest in public works would be heightened if fund-raisersutilized contests that awarded prizes to the first person who correctlyguessed what famous picture or photograph a UAV was painting on the sideof a building.

Referring to FIG. 14, method 1400 begins with process 1405, where aboundary of an object is defined and specified. Next, in process 1410, apaint profile is defined. As was indicated above, both of these taskscan be accomplished using paint profiles. One profile may be used tospecify the dimensions of an object to be painted, and indicate areaswhere no paint is to be applied. A second paint profile may be used tospecify the size, shape, and color of a painting that is to be placed onthe object to be painted. By merging these two paint profiles inaccordance with example embodiments, the resulting paint profilespecifies exactly where the UAV component of the UAS should apply paint,and the color of paint to be applied.

Next, in process 1415, UAS orients UAV relative to the object (e.g.,building) to be painted and randomly selects a direction within theobject boundary in which to fly the UAV. As UAV is flown along therandomly selected flight path, UAS periodically calculates a position ofUAV within the boundary, in accordance with process 1420. After theposition determination of process 1420, UAS reaches decision process1425, where it determines if the position has been passed overpreviously (and therefore, already painted).

UAS is capable of storing a record of locations which have been painted,and if a position of the UAV is at a location which should be painted(in accordance with the paint profile) and it has already been paintedby the UAV, then UAV is commanded to continue along the randomlyselected flight path (process 1430), where it returns to process 1420where the next position along the randomly selected flight path iscalculated. On the other hand, if UAV is at a location that should bepainted and the location has not yet been painted, then UAS commands UAVto apply paint at the current position as indicated at process 1435.

After paint has been applied at process 1435, UAS determines whether UAVis still within the defined boundary of the object to be painted atprocess 1440. If UAV is still within the object boundary, it continuesalong its flight path (process 1430) and then calculates its newposition at process 1420. However, if UAV is no longer within theboundary of the object, UAS proceeds to decision process 1445, where itis determined if the entire paint profile has been completed. If so,then method 1400 ends at process 1450. If not, the UAS commands UAV toreturn to process 1415, where another flight path within the objectboundary is randomly selected, and the UAV changes direction andproceeds along this new direction.

From the viewpoint of an observer watching a UAS applying paint inaccordance with method 1400, it would appear as if a UAV component ofthe UAS was haphazardly following random flight paths along the side ofthe structure, periodically applying paint in a seemingly carelessfashion, yet over time and as more passes are made by the UAV across theboundary of the object, the details of the painting or mural wouldgradually begin to emerge.

Various changes and modifications to the embodiments of the presentdisclosure described herein will be apparent to those skilled in theart. Such changes and modifications can be made without departing fromthe spirit and scope of the present subject matter and withoutdiminishing its intended advantages. It is therefore intended that suchchanges and modifications be covered by the appended claims.

The invention claimed is:
 1. An Unmanned Aerial System (UAS) forapplying a liquid to a surface, the UAS comprising: an Unmanned AerialVehicle (UAV) including a body, flight control mechanisms connected tothe body, a boom extending radially outward from the body, and a bumperdisposed on a distal end of the boom, the UAV configured to receivefirst control signals and to adjust an operational configuration of theflight control mechanisms in response to the first control signals; adelivery assembly connected to the UAV, the delivery assembly configuredto receive second control signals and to apply the liquid to the surfacein response to the second control signals, the delivery assemblyincluding: a supply reservoir, the supply reservoir configured to holdthe liquid and remain on the ground while the UAV is in flight, a nozzledisposed on the distal end of the boom, the nozzle configured to applythe liquid to the surface, wherein the bumper is arranged to protect thenozzle if the bumper contacts the surface during flight, a first pumpcoupled to the UAV, the first pump configured to supply the liquid tothe nozzle, a tether comprising a flexible tube connected between thesupply reservoir and the first pump, a second pump connected to thesupply reservoir and the flexible tube, the second pump configured toforce the liquid from the supply reservoir, through the flexible tube,and to the first pump; and a control unit connected to the UAV, thecontrol unit configured to transmit the first and second control signalsto the UAV and the delivery assembly, respectively.
 2. The UAS of claim1, further comprising a ground-based control station, the ground-basedcontrol station comprising one selected from the group consisting of alaptop computer, a tablet, and a mobile phone.
 3. The UAS of claim 1,the tether further comprising a power supply line.
 4. The UAS of claim3, further comprising a power supply configured to provide electricalpower to the UAV and the delivery assembly via the power supply line. 5.The UAS of claim 1, wherein the UAV comprises a plurality of sensors,and wherein the system further comprises a plurality of reflectorsaffixed to the surface, wherein the sensors are configured to detect aposition of the UAV relative to the reflectors and generate thirdsignals associated with the position.
 6. The UAS of claim 5, wherein thecontrol unit is configured to determine the location of the UAV relativeto the reflectors based at least in part on the third signals.
 7. TheUAS of claim 6, wherein the control unit is configured to fly the UAValong a predetermined flight path proximate to the surface to apply theliquid in a predetermined pattern.
 8. The UAS of claim 6, wherein thecontrol unit is configured to fly the UAV in a plurality of randomlydetermined directions proximate to the surface and to apply the liquidat predetermined positions along the randomly determined directions,such that over time the liquid is applied to the surface in apredetermined pattern.
 9. The UAS of claim 1, the tether furthercomprising a magnetic quick-release configured to separate the tetherfrom the UAV in the event of an emergency.
 10. The UAS of claim 1,wherein the nozzle is disposed at a distal end of the boom, and whereinthe nozzle, boom, and flight control mechanisms are disposed such thatthe nozzle is located further from a center of the body than the flightcontrol mechanisms.
 11. An Unmanned Aerial System (UAS) for applying aliquid to a surface, the UAS comprising: an Unmanned Aerial Vehicle(UAV) including rotors, a body, a boom coupled to the body, a bumperdisposed at a distal end of the boom, and a plurality of sensorsdisposed at the distal end of the boom, the plurality of sensorsconfigured to detect, to the nearest centimeter, a position of thesensors relative to the surface, the UAV configured to receive firstcontrol signals and to adjust an operational configuration of the rotorsin response to the first control signals; a liquid delivery assemblyconnected to the UAV, the liquid delivery assembly including a nozzle,the nozzle disposed at the distal end of the boom, the boom, rotors, andnozzle arranged such that the nozzle is disposed further away from thebody than the rotors, the liquid delivery assembly configured to receivesecond control signals and to apply the liquid to the surface with thenozzle in response to the second control signals, and a control unitconfigured to transmit the first control signals and the second controlsignals to the UAV and the liquid delivery assembly, respectively, thecontrol unit configured to calculate a position of the nozzle relativeto the surface based at least upon the position of the sensors relativeto the surface, the control unit configured to automatically adjust theoperational configuration of the rotors in response to the calculatedposition of the nozzle relative to the surface such that the UAV travelsalong a predetermined flight path adjacent to the surface and the nozzleis maintained at an optimum distance from the surface as the UAV travelsalong the predetermined flight path, wherein the optimum distance isless than thirty centimeters, and wherein the bumper is arranged toprotect the nozzle and the sensors if the bumper contacts the surfaceduring travel of the UAV along the predetermined flight path.
 12. TheUAS of claim 11, wherein, the liquid delivery assembly furthercomprises: a supply reservoir, the supply reservoir configured to holdthe liquid and remain on the ground while the UAV is in flight; a firstpump coupled to the UAV, the first pump configured to supply the liquidto the nozzle; a tether comprising a flexible tube coupled between thesupply reservoir and the first pump; and a second pump coupled to thesupply reservoir and the flexible tube, the second pump configured toforce the liquid from the supply reservoir, through the flexible tube,and to the first pump.
 13. The UAS of claim 11, wherein the deliveryassembly comprises: a cradle configured to hold an aerosol can, theaerosol can including a spring valve; and an actuator configured todepress the spring valve of the aerosol can in response to one of thesecond control signals.
 14. An Unmanned Aerial Vehicle (UAV),comprising: a body; a rotor coupled to the body, an operationalconfiguration of the rotor responsive to a first control signal; a boomcoupled to the body; a nozzle coupled to a distal end of the boom, anoperational configuration of the nozzle responsive to a second controlsignal, the rotor, boom, and nozzle arranged such that the nozzle isdisposed further away from the body than the rotor; a bumper disposed atthe distal end of the boom; a sensor disposed at the distal end of theboom, the sensor configured to generate a detection signal associatedwith a distance between the sensor and a surface disposed proximate tothe sensor; a control unit configured to calculate a distance betweenthe nozzle and the surface based at least upon the detection signal, thecontrol unit configured to generate the first control signal based atleast upon the distance between the nozzle and the surface toautomatically adjust the operational configuration of the rotor suchthat the UAV travels along a predetermined flight path adjacent to thesurface and the nozzle is maintained at an optimum distance from thesurface as the UAV travels along the predetermined flight path, whereinthe optimum distance is less than thirty centimeters, and wherein thebumper is arranged to protect the nozzle and the sensor if the bumpercontacts the surface during travel of the UAV along the predeterminedflight path.